Dynamo-electric machine.



No. 870,035. PATENTBD NOV. 5, 1907. D. 0. JACKSON.

DYNAMO ELECTRIC MACHINE.

APPLICATION TILED D110, 22, 1902.

2 SKEETSSHEET l.

Wain a5 5 as 11??- PATENTED NOV. 5, 1907.

D. G. JACKSON.

DYNAMO ELECTRIC MACHINE.

APPLICATION FILED DEC. 22 1902.

1.121;; :EluqAm l: -JACKjEL DUGALD C. JACKSON, OF MADISON, WISCONSIN.

DYNAHO-ELECTBIC MACHINE Specification of Letters Patent.

Patented Nov. 6, 1907.

Application and December 22.19am smart. 186.144.

To all whom it may concern:

Be it known that I, DUGALD C. JACKSON, a citizen of the United States, residing at Madison, in the county of Dane and State of Wisconsin, have invented a certain new and useful Improvement in Dynamo-Electric Machines, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification. 1

My invention relates to dynamo electric machines to be used for the generation or translation of pulsating or alternating electric currents. V

More particularly, my invention has reference to i such machines adapted for use with what are commonly known as single phase alternating currents.

-Polyphase alternating currents have been used with considerable success for the transmission of alternating currents for power purposes, but on account of the number of electrical conductors required there is an advantage in utilizing single phase alternating cur- .rents for power purposes. Furthermore, it is frefull speed by some outside means.

My invention has for one of its objects the provision of a motor which may be operated by currents supplied from a single phase alternating current system and which at the same time will be self-starting.

In order to make such a m0tor.self-starting, it has been proposed to wind the motor rotor or armature with an auxiliary commutated winding. A pair of brushes, when properly brought into contact with the commutator of such a winding, and when suitably connected, serve to throw the currents and corresponding poles induced in the armature out of equilibrium with the poles set up in the field winding, and thereby cause a starting torque upon what is frequently knownas the repulsion principle. In addition to the commutated winding, such motors have been provided with a closed circuit or squirrel cage winding, such as is common in induction motors. This squirrel cage winding may be utilized to provide for the normal operation of the motor after it has been brought'up to speed by the.

the point of highest potential. In order to prevent such sparking, my invention provides conductors or resistances connecting commutator bars. These resistances connecting adjacent or alternate commutator bars do cause a decrease in the starting torque, but the resistances may be made such that the reduction is immaterial. After the rotor attains its normal speed, the resistances, which, indeed, serve to close the armature coils, provide a secondary closed winding, which, if desired, may act in conjunction with an associated squirrel cage winding 'to cause the rotation of the motor on the induction principle. By making the connections between adjacent commutator bars of comparatively low resistance, it is possibleto allow the auxiliary winding to serve partially as a commutated winding for starting purposes and partially, in conjunction with the interposed resistances, as a closed coil induction motor armature winding; that is, the additional squirrel cage winding per so may be done away with.

posed between adjacent commutator bars and thereafter decreased until, indeed,-the commutator may be entirely short-circuited, thus producing a short-circuited armature winding. The interposition of-such resistances between commutator bars serves to prevent the injurious sparking previously referred to. V

The regulation of a motor provided with both an auxiliary commutated winding and a separate closed circuit winding may be excellent. In such a device the advantages of a large torque at starting, due to the reactions of the commutated winding, are combined with the characteristic regulation of the short-circuited induction motor armature winding which regulation is similar to that in a direct current, shunt wound motor. These advantages in regulation, however, may be gained equally well by the use of a single winding provided with a commutator between the bars of which suitable resistances may be connected. In order to vary and control the speed of the motor a variable resistance may be connected in the circuit between the brushes carrying the commutated current. In some cases I find it desirable to bring the conductor connecting the brushes int-o inductive relation with the motor field winding, whereby the currents through the commutated winding may be modified by the currents induced inthe said conductor by the inductive relation to the motor field winding.

I shall more fully explain my invention by reference to the accompanying drawings, in which- Figure 1' is a diagrammatic representation of a motor ditioooltorquoproduofng moons acting in harmony V constructed. accordance with my invention; Fig. 2is a modification thereof, showing the useof the inductive'relation between the-field windings and the; conductor connecting the brushes; Fig. 3 isa view show; 5 mg a dqi mble modilit'ationtin the construction of a momma r for to in connection Wit/i; 112 motor r y r I Y the mains S, 8, leading to the alternating current genresistance 19 the commutatedwindingbecomes a posits poles within the ring 6, which poles are of alterring armature. This winding is connected at intert VI'PW 1 1} woos. ootzbn illustrati g a mitt (it ('(lili'itlltt itttttll at! at ntaton bars; Fig. 5 is an end elevation of'the same.

I have shown a preferably laminated 'field ring .6, provided with the usual induction motor fi'eld winding 7, lwhich is supplied with alternating current through erator 9. As is well understood by those skilled in the art, this winding serves to produce diametrically opnat-ing polarity. Mounted to rotate within the ring 6 is the armature 10. In this embodiment of my invcntion I have shown a closed circuit squirrel cage winding having conductors 11 and end connecting rings 12. In addition to this closed circuit winding the armature is wound with a commutated winding 13,. similar to that employed in a direct current 'Gramme vals, as shown, with the commutator 15. The brushes 16, 16 serve to connect substantially diametrically opposite sides of the commutator through the conductor 17 in whose circuit there is interposed the variable 'resistance 18. The resistances 19, '19 are permanently connected between adjacent commutator bars. Thus between adjacent commutator bars there-are provided parallel circuits, one through the correspondingly intermediate portion of the commutated winding and the other through the corresponding resistance 19. To the extent of the electrical path afforded through the closed circuit winding. From still,v another point of view the winding 13 will be seen to be connected at intervals through the conductors 20, 20 with a closed and conjunction with the torque producedtythe usual squire] cage winding. The vtritbloresistante 18 serves to regulate and control the current flowing between the brushes 16,-1o,-whereby"the starting torque may be controlled and varied at will and, in

deed,- ,the speed of the motor may be, to a certain extent, controlled by the amountof resistanceincluded' between. the brushes.

In Fig. 3 I have illustrated a commutator in which 'the' adjacent bars 21, 21 are electrically connected by 23, 23 may be left open or filled with suitable insulating material, in order to provide a smooth' running surface for the brushes bearing upon the commutator.

- In 4 and 5 I have illustrated a means. for varyingthe" resistances interposed between various comm'utator segments. {1 have illustrated a spider 24, splined upo'n the armature shaft 25 to rotate therewith.

Suitable resistances 26 are connected between brushes 2? mounted on the spider 24. By adjusting the position of the spider'an'd its associated brushes and resistances longitudinally with respect to the armature shaft, the amount of resistance interposed between adjacent commutator bars. may be varied'at will. -By entirelyremoving the spider from its association with the. commutator, the resistances between the bars may be entirely removed.- The alternate position of the spider may be arranged to produce a dead short: circuit between commutator bars, thus serving to short-circuit the cominutated winding.

ioo

ring of high resistance. In Fig. 2 I have illustrated a modification of Fig.

The operation of my improved motor is as follows: in which the squirrel cage winding is entirely dispensed Current being supplied to the field winding 7 poles with, the commutated winding being connected with of alternating polarity are set up in the field ring 6, a continuous ring-oi metal of suitable resistance to prowhereupon currents are induced in. the squirrel cage vide in addition to the short-circuiting pathfor the ararmature winding and in the commutated winding 13. mature coils a commutator for the commutation of sufii- The armature being stationary, the reactions caused cient current for the purpose of the necessary starting a by the currents induced in the squirrel cage winding torque. The single winding inthis case thus per are balanced, tending to cause no resultant rotation of forms the double function of both the closed circuit the armature in either direction. The brushes 16, 16, and the auxiliary winding shown in Fig, 1. In Fig. 2

however, being suitably placed between the neutral I have also shown auxiliary field coils 28,. 28, wound points and the points of highest potential on the com- -'on the field frame 6 in inductive relation to the primutator, serve to unbalance with respect to the field mary field winding 7. These coils 28 constitute an magnet the reactions set up by the currents in the auxiliary or supplemental field winding serving to incommutated winding. These unbalanced reactions fluence the amount of current traversing the auxiliary serve to cause a rotation of the armature uponwhat is armaturewinding and .thereby influencing the operacommonly known .as the repulsion principle. The tion of the machine. It will be seen that in these emarrnature being thus set in rotation, the reactions of the bodiments oimyjnvention I have shown a plurality short-circuited ,winding become unbalanced, producof closed circuits corresponding in number with the ing a torque in the same direction as that produced byarmature coils, each closed circuit including in series the reactions of the commutated winding. The motor an armature-coil, a resistance, and the armature con- 1'25 being thus brought into normal conditions of operation, nections with the commutator between which the rethe resistances 19 interposed between adjacent comsistance intervenes, the resistance thus bridging the mutator bars serve to carry the .currents which would commutator segments and forming with respect to adotherwise cause sparking at the commutator. These jacent commutator bars a second electrical path in parresistances, indeed, to the extent of their conducallel relation .with the associated; armature coil. It

will be apparent. that a brush bearing upon the commutator between the connections of the corresponding armature coil with the commutator is also put into parallel relation with the armature coil and the associated resistance.

1 have particularly described my invention with reference to a single phase system of power distribu tion, a two pole inducing field and two brushes being indicated to correspond with such conditions. O viously, the number of brushes may be varied, as desired, in accordance with the number of phases of current in the transmission circuit and the number of poles in the machine, l urtherinore, l have described my invention with particular refer nce to a motor adapted to lw operated by currents supplied from an alternating current transmission line. It will be apparent, however, that my inv ntion may readily be applied to alternating curr nt at ncmt rs.

I have described an embodiment of my invention in which the commutated armature winding is in the form of a closed coil Gramme ring winding. Any other suitable form of commutated winding may be em ployed, such as a well known progressive winding or an open coil winding, such as is frequently used in generators for supplying current to arc lighting circuits.

I have herein shown and particularly described the preferred mbodiment of my invention, but I do not wish to limit myself to the precise construction and arrangement herein shown, as modifications therein may readily be made by those skilled in the art, without departing from the spirit of my invention.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a dynamo electric machine, the combination with an armature winding, of a commutator therefor, said commutator having an integral conductor of high resistance and a contact surface for brushes, connected with said winding and with said high resistance conductor 2. In a system of electrical power transmission, the combination with a source of alternating current, of a motor receiving current from said source, the armature of said motor having a commutated winding. and an associated commutator therefor, said commutator having an integral conductor of high resistance and a contact sur face for brushes connected with said commutated Winding and with said high resistance conductor.

2!. In a dynamo electric machine. the combi.ation with an armature winding, of a commutator therefor, said commutator comprising an inteural ring conductor connected with said winding, and brushes in electrical connection with said ring conductor. 4

4. In a system of electrical power transmission, the combination with a source of alternating current, of a therewith, the said motor having its armatui p k niutator for said commutated winding, said comm with a short-circuited and a commutated winding. :1

having an integral conductor of high resistance and contact surface for brushes connected with said win" and with said high resistance conductor, brushes for gaging said commutator, and an auxiliary field winding r1: circuit with said brushes and the commutated winding, substantially as described.

6. in a system of power transmission, the combinati with a source of alternating current, of a. r tor in circa therewith, the said motor having ii uni:

with a sliort-circuited and a commut ed mutator for said commutated winding, S3541 "ommura comprising an integral ring conductor connected with winding, brushes for engaging said commutator, and circuit for impressing upon the brushes an (iQCilOliit !i\ force of the frequency of said Source .7. in a system of power transmission, the combinati u with a source of alternating current, of a motor in circirt' therewith. the said motor having its armature provid with a short-circuited and a commutated winding. a con mutator therefor. said commutator having an integrr' conductor of high resistance and a contact surface for brushes connected with said commutated winding and with said high resistance conductor, brushes bearing on the contact surface of said commutator, an external circuit connecting said brushes, and a suitable controller in said external circuit.

8. In a system of power transmision, the combination with a source of alternating current, of the field magnet e a motor in circuit with said source. an armature for s: motor, a winding on said armature, a commutator the for, said commutator comprising an integral ring Ct ductor connected with said winding, brushes in electrical connection with said ring conductor at points intermediate between the neutral plane and the plane of commutation. and an external electrical circuit joining said brushes.

9. In an alternating current dynamo electric machine, the combination with a field magnet, of an armature provided with a commutated winding, a commutator therefor, said commutator having an integral conductor of high resistance and a contact surface for brushes connected with said winding and withsaid high resistance conductor, brushes bearing on said commutator at points intermediate between the neutral plane and the plane of commutation, and an external circuit to which said brushes are connected.

In witness whereof, I hereunto subscribe my name this seventeenth day of December A. D., 1902.

DUGALD c. JACKSON,

Witnesses:

LYNN A. WrLLmls, Hnvsr Ii. Hanson. 

